NON-ROUND SOLUTION SPUN SPANDEX FILAMENTS AND METHODS AND DEVICES FOR PRODUCTION THEREOF

Abstract

Non-round or shaped solution spun spandex filaments as well as methods and devices for production of these non-round or shaped solution spun spandex filaments are provided.

Claims

1. A non-round or shaped solution spun spandex filament produced by solution dry spinning using a spinneret with a plate comprising two or more holes or capillaries spaced less than 0.05 inches apart and greater than 0.016 inches apart.

2. The spandex filament of claim 1 wherein the two or more holes or capillaries on the spinneret are spaced less than 0.038 inches apart.

3. The spandex filament of claim 1 wherein the two or more holes or capillaries on the spinneret are spaced less than 0.025 inches apart.

4. A non-round or shaped solution spun spandex filament produced by solution dry spinning using a spinneret with a plate comprising two or more holes or capillaries spaced less than 0.05 inches apart and greater than greater than 0.01 inches apart wherein the two or more holes on the spinneret are connected via a narrow rectangular slot 0.0030 inches wide.

5. The spandex filament of claim 4 wherein the two or more holes or capillaries on the spinneret are spaced less than 0.038 inches apart.

6. The spandex filament of claim 4 wherein the two or more holes or capillaries on the spinneret are spaced less than 0.025 inches apart.

7. The spandex filament of claim 4 wherein the two or more holes or capillaries on the spinneret are spaced less than 0.020 inches apart.

8. The spandex filament of claim 7 wherein the two or more holes or capillaries on the spinneret are spaced 0.015 inches apart.

9. A non-round or tri-lobal shaped solution spun spandex filament produced by solution dry spinning using a spinneret with a plate comprising three holes or capillaries, wherein said holes or capillaries are between 0.009 to 0.015 inches in diameter and oriented in a triangular configuration.

10. The spandex filament of claim 9 wherein the triangular configuration is equilateral.

11. The spandex filament of claim 9 wherein the holes or capillaries on the spinneret are connected via narrow rectangular slots 0.0030 inches wide.

12. The spandex filament of claim 9 wherein the holes or capillaries are connected via rectangular slots radiating from the center of the capillary cluster to each of the holes capillaries less than 0.0300 inches from the center point, the slot being 0.055 inches wide.

13. A method for producing non-round or shaped solution spun spandex filaments of claim 1, said method comprising forcing a polymer spinning solution through said spinneret.

14. A method for producing non-round or shaped solution spun spandex filaments of claim 4, said method comprising forcing a polymer spinning solution through said spinneret.

15. A method for producing non-round or shaped solution spun spandex filaments of claim 9, said method comprising forcing a polymer spinning solution through said spinneret.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0023] FIG. 1A is a diagram of a nonlimiting embodiment of a spinneret used in production of non-round or shaped solution spun spandex filaments. In this nonlimiting embodiment, the holes or capillaries of the spinneret are spaced 0.023 inches apart from their centers.

[0024] FIG. 1B is a cross-sectional view of a non-round or shaped solution spun spandex filament produced with the spinneret of FIG. 1A.

[0025] FIG. 2A is a diagram of a nonlimiting embodiment of a spinneret used in production of non-round or shaped solution spun spandex filaments. In this nonlimiting embodiment, the holes or capillaries of the spinneret are spaced 0.0150 inches apart from their centers and are connected via a narrow slot 0.0030 inches wide.

[0026] FIG. 2B is a cross-sectional view of a non-round or shaped solution spun spandex filament produced with the spinneret of FIG. 2A.

[0027] FIG. 3A is a diagram of a spinneret used in production of solution spun spandex filaments. In this embodiment, the holes or capillaries of the spinneret are spaced 0.050 inches apart from their centers.

[0028] FIG. 3B is a cross-sectional view of a solution spun spandex filament produced with the spinneret of FIG. 3A.

[0029] FIG. 4A is a diagram of a nonlimiting embodiment of a spinneret used in production of a non-round or shaped solution spun spandex filaments. In this nonlimiting embodiment, there are three holes or capillaries in the spinneret spaced 0.0289 inches from the center of the cluster connected via a rectangular slot 0.055 inches wide

[0030] FIG. 4B is a cross-sectional view of a non-round or shaped solution spun spandex filament produced with the spinneret of FIG. 4A.

[0031] FIG. 5A is a diagram of a nonlimiting embodiment of a spinneret used in production of a coalesced spandex threadline comprised of three non-round filaments. In this nonlimiting embodiment, there are three pairs of holes or capillaries where the spacing between holes or capillaries within a pair is 0.023 inches and the spacing between the centerlines of the pairs is 0.529 inches.

[0032] FIG. 5B is a cross-sectional view of a non-round or shaped solution spun spandex filament produced with the spinneret of FIG. 5A.

[0033] FIG. 6 is a diagram of a nonlimiting embodiment of a spinneret used in production of a non-round or shaped solution spun spandex filaments. In this nonlimiting embodiment, there are three holes or capillaries in the spinneret with the individual holes located at the vertices of an equilateral triangle with sides of 0.023 inches.

DETAILED DESCRIPTION OF THE INVENTION

[0034] The inventors herein have now found that non-round or shaped solution spun spandex filaments such as, but not limited to, dogbone or peanut-shaped filaments, provide more surface area and thinner films that can promote drying.

[0035] Provided by this disclosure is non-round or shaped solution spun spandex filaments as well as methods and devices for their production.

[0036] The term “spandex”, as used herein, has its usual definition, a long-chain synthetic polymer that comprises at least 85% by weight segmented polyurethane.

[0037] By “non-round or shaped solution spun spandex filaments” as used herein, it is meant to be inclusive of multilobal filaments such as, but not limited to, dogbone, peanut-shaped or bilobal filaments as well as filaments with 3, 4, 5 or 6 or more lobes. Lobes may be similar in size or varied in size depending upon the application.

[0038] FIGS. 1A, 2A, 4A, 5A and 6 depict nonlimiting embodiments of spinnerets useful in production of the non-round or shaped solution spun spandex filaments. As shown therein, the spinnerets may comprise two or more holes, also referred to herein interchangeably as capillaries. In one nonlimiting embodiment, the holes or capillaries are between 0.009 and 0.025 inches in diameter. The holes or capillaries may be separated as depicted in FIGS. 1A and 5A or connected as depicted in FIGS. 2A and 4A via narrow rectangular slots. In one nonlimiting embodiment, the narrow rectangular slot is between 0.0025 and 0.006 wide. In one nonlimiting embodiment, the narrow rectangular slot is 0.0055 inches in width. As shown by comparison of FIG. 1B to FIG. 3B, spacing of these holes or capillaries may be critical to desired formation of the non-round or shaped solution spun spandex filament. Spacing, as measured from the centers of the holes or capillaries is preferably less than 0.05 inches, less than 0.04 inches, less than 0.038 inches, less than 0.035 inches, less than 0.030 inches, or less than 0.025 inches, and greater than 0.016 inches, or greater than 0.018 inches, when separated. Spacing, as measured from the centers of the holes or capillaries is less than 0.05 inches, less than 0.04 inches, less than 0.038 inches, less than 0.035 inches, less than 0.03 inches, less than 0.025 inches, or less than 0.020 inches and greater than 0.01 inches, or equal to 0.015 inches apart, when connected.

[0039] FIG. 6 shows a spinneret with a plate comprising three holes or capillaries. In this nonlimiting embodiment, the holes are between 0.009 to 0.015 inches in diameter and oriented in an equilateral triangular configuration. These holes are juxtaposed to form a cluster. In one nonlimiting embodiment, the holes may be connected via rectangular slots radiating from the center of the capillary cluster to each of the capillaries as shown in FIG. 4A. In one nonlimiting embodiment, the rectangular slot is 0.0030 inches in width. In one nonlimiting embodiment, the holes or capillaries are connected via rectangular slots radiating from the center of the capillary cluster to each of the holes capillaries less than 0.0300 inches from the center point, the slot being 0.055 inches wide. These plates are useful in accordance with the present invention to form non-round or tri-lobal shaped solution spun spandex filament by solution dry spinning.

[0040] Accordingly, an aspect of the present invention relates to a non-round or shaped solution spun spandex filament produced by solution dry spinning using a spinneret with a plate comprising two or more closely spaced grouped holes or capillaries.

[0041] In one nonlimiting embodiment, the non-round or shaped solution spun spandex filaments are produced by solution dry spinning using a spinneret with a plate comprising two or more holes or capillaries spaced less than 0.05 inches apart and greater than 0.016 inches, more preferably greater than 0.018 inches, apart. In one nonlimiting embodiment, the non-round or shaped solution spun spandex filaments are produced by solution dry spinning using a spinneret with a plate comprising two or more holes or capillaries spaced less than 0.025 inches apart and greater than 0.016 inches, more preferably greater than 0.018 inches, apart. In one nonlimiting embodiment, the non-round or shaped solution spun spandex filaments are produced by solution dry spinning using a spinneret with a plate comprising two or more holes or capillaries spaced less than 0.05 inches apart and greater than 0.01 inches apart, wherein the holes or capillaries are connected via a narrow rectangular slot 0.0030 inches wide. In one nonlimiting embodiment, the holes or capillaries are between 0.009 to about 0.0230 inches in diameter.

[0042] In one nonlimiting embodiment, a non-round or tri-lobal shaped solution spun spandex filament is produced by solution dry spinning form using a spinneret with a plate comprising three holes or capillaries. In this nonlimiting embodiment, the holes are between 0.009 to 0.015 inches in diameter and oriented in an equilateral triangular configuration. These holes are juxtaposed to form a cluster. In one nonlimiting embodiment, the holes may be connected via rectangular slots radiating from the center of the capillary cluster to each of the capillaries as shown in FIG. 4A. In one nonlimiting embodiment, the rectangular slot is 0.0030 inches in width. In one nonlimiting embodiment, the holes or capillaries are connected via rectangular slots radiating from the center of the capillary cluster to each of the holes capillaries less than 0.0300 inches from the center point, the slot being 0.055 inches wide.

[0043] Another aspect of the present invention relates to spinnerets for production of non-round or shaped solution spun spandex filaments.

[0044] In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.05 inches apart and greater than 0.016 inches, more preferably greater than 0.018 inches, apart. In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.025 inches apart and greater than 0.016 inches, more preferably greater than 0.018 inches, apart.

[0045] In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.05 inches apart and greater than 0.01 inches apart, wherein the holes or capillaries are connected via a narrow rectangular slot 0.0030 inches wide. In one nonlimiting embodiment, the two or more holes or capillaries on the spinneret are spaced less than 0.020 inches apart. In one nonlimiting embodiment, the two or more holes or capillaries on the spinneret are spaced 0.015 inches apart.

[0046] In one nonlimiting embodiment, each capillary or hole is between 0.009 to 0.025 inches in diameter.

[0047] In one nonlimiting embodiment, the spinneret comprises a plate comprising three holes or capillaries. In this nonlimiting embodiment, the holes are between 0.009 to 0.015 inches in diameter and oriented in an equilateral triangular configuration. These holes are juxtaposed to form a cluster. In one nonlimiting embodiment, the holes may be connected via rectangular slots radiating from the center of the capillary cluster to each of the capillaries as shown in FIG. 4A. In one nonlimiting embodiment, the rectangular slot is 0.0030 inches in width. In one nonlimiting embodiment, the holes or capillaries are connected via rectangular slots radiating from the center of the capillary cluster to each of the holes capillaries less than 0.0300 inches from the center point, the slot being 0.055 inches wide.

[0048] In these embodiments, the spinneret may comprise multiple groups of these closely spaced holes or capillaries for production of multiple threadlines containing one or more non-round filaments.

[0049] The spinneret may be made from a variety of materials suitable for the manufacture of spandex spinnerets. A nonlimiting example is 317 stainless steel.

[0050] As will be understood by the skilled artisan upon reading this disclosure, the dimensions and shape of the spinneret as well as the number of closely spaced holes or capillaries can be selected to be compatible with the geometry of the spin cell, such as round or rectangular, and the number of filaments desired.

[0051] Another aspect of the present invention relates to a method for producing non-round or shaped solution spun spandex filaments. In the solution dry spinning method, the spandex polymer is made by a two-step process. In the first step, an isocyanate-terminated urethane prepolymer is formed by reacting a polymeric glycol with a diisocyanate. Typically, the molar ratio of the diisocyanate to the glycol is controlled in a range of 1.50 to 2.50. If desired, catalyst can be used to assist the reaction in this prepolymerization step. In the second step, the urethane prepolymer is dissolved in a solvent such as N,N-dimethylacetamide (DMAc) and is chain extended with a short chain diamine or a mixture of diamines to form the spandex solution. Various additives can be added to the spandex polymer solution to improve the appearance, performance and quality in manufacture, storage, processing and use of the fiber. In this method, the polymer spinning solution is pumped into a spinning cell where it is converted into fibers by forcing the polymer solution through a spinneret comprising a plate with two or more closely spaced holes or capillaries.

[0052] In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.05 inches apart and greater than greater than 0.016 inches, more preferably greater than 0.018 inches, apart. In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.025 inches apart and greater than 0.016 inches, more preferably greater than 0.018 inches, apart.

[0053] In one nonlimiting embodiment, the spinneret comprises a plate with two or more holes or capillaries closely spaced less than 0.05 inches apart and greater than 0.01 inches apart, wherein the holes or capillaries are connected via a narrow rectangular slot 0.0030 inches wide. In one nonlimiting embodiment, the two or more holes or capillaries on the spinneret are spaced less than 0.020 inches apart. In one nonlimiting embodiment, the two or more holes or capillaries on the spinneret are spaced 0.015 inches apart.

[0054] In one nonlimiting embodiment, the spinneret comprises a plate comprising three holes or capillaries. In this nonlimiting embodiment, the holes are between 0.009 to 0.015 inches in diameter and oriented in a equilateral triangular configuration. These holes are juxtaposed to form a cluster. In one nonlimiting embodiment, the holes may be connected via rectangular slots radiating from the center of the capillary cluster to each of the capillaries as shown in FIG. 4A. In one nonlimiting embodiment, the rectangular slot is 0.0030 inches in width. In one nonlimiting embodiment, the holes or capillaries are connected via rectangular slots radiating from the center of the capillary cluster to each of the holes capillaries less than 0.0300 inches from the center point, the slot being 0.055 inches wide.

[0055] In any of these embodiments, the spinneret may comprise multiple groups of the closely spaced holes or capillaries within a single spinning cell to produce multiple threadlines containing one or more non-round filaments.

[0056] As the closely spaced, adjacent filaments exit the spinneret they fuse to form a non-round or shaped solution spun spandex filament. Preferred is that the fusing of the filaments occur in a region where the solvent concentration is sufficient to form a fully fused filament. A number of the fused filaments may be coalesced further down the cell by means of a false twist jet located below the cell exit to provide a final product of the desired thickness. The twist action of the false jet propagates up the cell to a location where the filaments are somewhat dry, but are sufficiently tacky to adhere and form a coalesced threadline comprised of multiple non-round filaments. After exiting the spin cell, the spandex threadline may be treated with a finish to improve threadline lubricity and reduce tack on the package.

[0057] The following section provides further illustration of the non-round or shaped solution spun spandex filaments of the present invention as well as the spinnerets and methods for their production. These working examples are illustrative only and are not intended to limit the scope of the invention in any way.

EXAMPLES

Example 1: Production of 22/1 862W Non-Round or Dogbone-Shaped Filament

[0058] A 22 dtex mono-filament dogbone spandex produced in accordance with the present invention using a spinneret as depicted in FIG. 2A was evaluated.

[0059] The spin process was found to run with an acceptable break level. The cross-section of the resultant spandex threadline is shown in FIG. 2B. The strength and elastic properties of the spandex threadlines were measured in accordance with the general method of ASTM D 2731-72. Three filaments, a 2-inch (5-cm) gauge length and a 0-300% elongation cycle were used for each of the measurements. The samples were cycled five times at a constant elongation rate of 50 centimeters per minute. Load power, the stress on the spandex during initial extension, was measured on the first cycle at 200% extension and is reported as centinewtown (cN) per threadline. Unload power is the stress at an extension of 200% for the fifth unload cycle and is also reported in centinewton (cN). Percent elongation at break and tenacity were measured on a sixth extension cycle. Table 1 shows the physical properties for the 22 dtex mono-fil dogbone spandex samples.

TABLE-US-00001 TABLE 1 Physical properties of 22 dtex mono-fil dogbone shape threadline Dogbone Test Metrics Mono-filament Decitex 22 First cycle load power at 200% 2.5 elongation, cN Fifth cycle unload power at 0.52 200% elongation, cN Elongation to break, % 494 Breaking force, cN 18.8

Example 2: Production of 44 Dtex 3-Fil Spandex

[0060] Samples of a 44 dtex 3-fil spandex were produced via conventional spandex dry spinning process using a spinneret as depicted in FIG. 5A. The break level during spinning was acceptable. The cross-section of the resultant threadline is shown in FIG. 5B. Physical properties of the spandex are shown in Table 2.

TABLE-US-00002 TABLE 2 Physical properties of 44 dtex 3-filament coalesced non-round, dogbone shape threadline 44 dtex 3-filament coalesced Test Metrics dogbone filaments Decitex 44 First cycle load power at 200% 6.5 elongation, cN Fifth cycle unload power at 1.01 200% elongation, cN Elongation to break, % 480 Breaking force, cN 31.1

Example 3: Production of a Series of 22 Dtex Mono-Fil Spandex Fibers

[0061] A series of 22 dtex mono-fil spandex fibers were produced at constant spinning conditions using a spinneret with round holes or capillaries, a spinneret with holes or capillaries as shown in FIG. 2A and a spinneret with holes or capillaries as shown in FIG. 4A at identical spinning conditions. Each of the fibers was analyzed for residual solvent. Results of the analysis are shown in Table 3.

[0062] DMAc in spandex yarn is determined by extraction in a solvent and the DMAc in the extract analyzed by gas chromatography with a flame ionization detector. The solvents used may be a polar organic solvent such as methanol or water.

[0063] The analysis method is as follows: (1) place 2±0.2 g of spandex yarn in a vial with sealable cap and add 50 mL of solvent; (2) place the sample vial in a heating block or oven and heat to approximately 60° C. for at least 15 minutes; (3) place an aliquot of the solvent in a GC vial for analysis; (4) analyze the sample solution by GC-FID; and (5) determine the DMAc concentration in solution relative to a known standard or standard calibration curve.

[0064] DMAc concentration in yarn was determined using the following calculation:

DMAc concentration in spandex yarn, wt. %=DMAc concentration in solvent (μg/mL)*50 mL solvent*dilution factor*100% Weight of Yarn extracted (g)*1,000,000 (μg/g)

[0065] where dilution factor=4 for a 1:4 dilution or 1 for no dilution

TABLE-US-00003 TABLE 3 Residual solvent level of spandex produced from various capillary shapes Hole or capillary Hole or capillary Round hole as shown in as shown or capillary FIG. 2A in FIG. 4A Residual Solvent, 0.98% 0.79% 0.70% wt. %